Lymphomas

The lymphatic system is a complex network of lymphoid organs, lymph nodes, lymph ducts, lymphatic tissues, lymph capillaries and lymph vessels that produce and transport lymph fluid from tissues to circulatory system. The lymphatic system is a major component of the immune system.

The lymphatic system has three interrelated functions: removal of excess fluids from body tissues, absorption of fatty acids and subsequent transport of fat (chyle) to the circulatory system and production of immune cells such as lymphocytes.

Lymph originates as blood plasma that leaks from the capillaries of the circulatory system, becoming interstitial fluid, and filling the space between individual cells of tissue.

Lymphomas

Lymphoma is the name of a diverse group of cancers of the lymphatic system, a connecting network of glands, organs and vessels whose principle cell is the lymphocyte.

Lymphomas are grouped into major categories: Hodgkin's disease and non-Hodgkin's lymphomas.

Lymphomas usually originate in the lymph nodes located throughout the body, but they can arise from lymphoid tissue that does not form distinct nodes, such as that in the gastrointestinal tract or lung.

Causes

The etiology of most lymphoma is unknown. In experimental and domestic animals, viruses can cause lymphomas. Burkitt's lymphoma, a type of lymphoma that is rare but relatively common in children of central Africa, is though to be caused by Epstein-Barr virus, a member of the herpes virus group.

Signs And Symptoms

Patients with lymphoma may have painless swelling of various lymph nodes, such as those in the neck. Some patients with fever, malaise, and weight loss. If the lymphoma originates in lymphoid tissue outside the lymph nodes, abdominal pain will signal lymphoma of the gastrointestinal tract and a cough will point to lymphoma of the lung.

Lymph nodes involved by lymphoma are characteristically enlarged. They may be firm and have a consistency resembling fish flesh. In rare cases they are rock hard and they may show areas of cellular death (necrosis).

Classification

By using modern immunologic techniques, most lymphomas can be identified as B-cell, T-cell; about 90% of lymphomas are of B-lymphocyte origin.

Broadly, lymphoma is categorized as Hodgkin's lymphoma and non-Hodgkin lymphoma (all other types of lymphoma).

Non-Hodgkin's Lymphoma

NHL describes a group of cancers arising from lymphocytes. It is distinct from Hodgkin lymphoma in its pathological features, epidemiology, common sites of involvement, clinical behavior, and treatment. The non-Hodgkin lymphomas are a diverse group of diseases with varying courses, treatments and prognoses.

WHO Classification

This classification attempts to classify lymphomas by cell type, the normal cell type that most closely resembles the tumor. They are classified in three large groups; the B cell tumors, the T cell and natural killer cell tumor, Hodgkin lymphoma and other minor groups.

Diagnosis

Most diagnoses of lymphoma are made by surgical removal of a lymph node. Once a diagnosis of lymphoma is established, the patient usually must undergo a series of staging studies. These include a liver-spleen scan to determine if those organs are involved as well as a bone marrow biopsy to check for the presence of malignant cells.

Treatment

The treatment of lymphomas depends on the type of lymphoma diagnosed. Lymphomas in low grade group are usually not treated, since treatment does not increase life expectancy.